US1901919A - Art of telephony signaling - Google Patents

Description

March 21, 1933. c, A, MOKEE 1,901,919

ART OF TELEPHONY SIGNALING Filed June 21, 1929 5 i K H '3 f INVENTOR. (70/?062 4 Mfikee A TTORNE Y.

Patented Mar. 21, 1933 UNITED STATES PATENT OFFICE CLARENCE A. MCKEE, OF BRONX, NEW YORK, ASSIGNOB, BY MESNE ASSIGNMENTS, TO

WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A. CORPORA- TION OF NEW YORK ART OF TELEPHONY SIGNALING Application filed June 21,

This invention relates to signaling in telephony and more particularly to call signals which are usually characterized by the employment of a so-called ringing circuit in which is included a bell or other audible signaling device signaling a call to a subscriber or station.

In many instances, it is found desirable to signal the subscriber or station visually instead of audibly while in other cases both audible and visual signals: are preferred. No satisfactory method or means to accomplish this result has heretofore been suggested for use in commercial telephone systems, while in private intercommunicati ng systems the only practical results thus far obtained are through the case of independently energized local circuits acting through either automatic or manual control devices. Relatively weak currents are employed for the bell-ringing circuits and in order to produce a visual signal such a circuit has been utilized to operate a relay in a local circuit to complete the latter and thus energize a lamp included therein.

The use of local circuits to light lamps, as heretofore, is open to many practical disadvantages. For example, ordinary commercial lighting current is generally used and this, of course, necessitates the careful and adequate insulation throughout the system with attendant expense. In many instances, moreover, current outlets are not convenient, and long leads through armored cable and conduit are required with incident expense and frequently unsightly installation.

/Vith the foregoing consideration-s in mind, the object of the present invention is to produce a visual signal in the ringing circuit without necessitating the employment of relays or manually controlled devices and without any other extraneous source of current supply.

The method of this invention consists, generally speaking, in passing an alternating ringing current through both visual and audible signaling devices or through a visual signal device alone, while precluding the flow of direct current through such devices 1929. Serial No. 372,586.

at all times. Another phase of the present i v Features of the invention, other than those specified, will be apparent from the hereinafter detailed description and claim, when read in conjunction with the accompanying drawing.

In the accompanying drawing, I have illustrated different wiring diagrams showing the manner in which the method of this invention may be practically carried out, but the showing therein made is to be understood as illustrative, only, and not as de fining the limits of the invention.

Figures 1, 2 and 3 show wiring diagrams illustrating difierent Ways of practicing this invention.

Referring to the drawing, 1 designates a bell ringing circuit and in which circuit is included the usual polarized bell or buzzer 2, and a condenser 3. The circuit as thus far described is a conventional bell ringing circuit employing alternating current for the operation of the bell. The present invention may be associated with this: conventional circuit in various ways. For example, as shown in Figure 1, a circuit 4% may be connected into the circuit 1, so as to shunt the bell 2 and the condenser 3 and in this circuit 4 is included a condenser 5 and a visual signal 6.

In the showing of Fig. 2, the circuit 40 is connected into the circuit 1, so as to merely shunt the bell 2. The circuit 4a; includes the visual signal 6, but does not require a condenser corresponding to the. condenser 5.

In the showing of' Fig. 3, a circuit 4?; is connected into the circuit 1, so as to shunt both the bell 2 and condenser 3 and said circuit 4?) includes a condenser 55 and the primary coil 7 of a step-up transformer. The secondary 8 of which transformer is included in a circuit 9 which also includes a visual signal 6. As a modified form of the construction of Figure 3, the condenser 51) may be omitted and the circuit 4?) arranged so as to merely shunt the bell 2 after the manner illustrated in Fig. 2. Thus, the condenser 3 of the bell ringing circuit may function in this circuit alone or may serve to function for both the circuits 1 and 4a or 1 and 4b. The purpose of employing a condenser in series with the visual signal is to preclude passage of direct current through the visual signal and thus preclude normal short circuiting of the direct current circuits of the telephone system, irrespective of the kind of visual signaling device employed.

With the arrangements described in the several figures, the visual signal is arranged, in effect, in multiple with the audible signal 2, and these signals are therefore operated simultaneously when the circuit 1 is completed from the central oilice or through Switchboard connection, or in any other suitable way known to the art for energizing bell ringing circuits.

In practice it is feasible to either mute the audible signal or to omit it from the ringing circuit although in most installations, it is desirable to operate the two alarms simultaneously. Furthermore, these two alarms may be positioned at widely separated places to be heard and observed respectively by different persons. It is also within the purview of this invention to include in the shunt circuits described more than one visual signal, this being preferably accomplished by connecting such visual signals in the shunt circuit, for example the circuit 4, in multiple.

I wish to call particular attention to the fact that the current for energizing the visual signal is derived from the ringing circuit, i. e., it is the ringing current. In practice, this current has heretofore generally been so weak, for reasons well understood in the art, that it will not operate well known lamps used for signaling purposes in telephony generally. I have discovered, however, that even with a weak current ordinarily used, it is entirely feasible to obtain thoroughly satisfactory visual signalin through the employment of non-filament tubes, such, for instance, as a neon tube. Tubes of this character are found to operate with high efiiciency in a ringing circuit and the current consumption thereof is practically negligible. Furthermore, they will operate on a very weak alternating current, such as is generally employed in the bell ringing circuits of telephones.

It is, moreover, practical in some instances to utilize a neon tube in the manner described without a condenser in series, but for certain other types of visual signaling devices which may be employed, the presence of a condenser in series therewith is not only desirable but necessary to preclude shorting. The economy of current consumption of tubes of the character described makes it possible to connect such a tube in multiple relation with a polarized bell in a ringing circuit without appreciably affecting the operation of the bell under normal current conditions.

I have specifically referred to neon tubes as illustrative of the present invention, but I wish it understood that I do not limit the invention to this particular tube, as other suitable equivalent visual signaling devices may be used for this purpose.

The foregoing detailed description sets forth the invention in its preferred practical forms and defines the preferred manner of practising the invention, but said invention is to be understood as fully commensurate with the appended claim.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is:

In a telephone signaling system, the combination of an alternating current ringing circuit, a condenser and an audible signaling device included in series in said circuit, and a circuit connected to the ringing circuit and shunting said condenser and audible signaling device, said shunt circuit including a condenser and a visual signaling device.

In testimony whereof I have signed the 1

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